It’s called absurdity. It’s funny because it’s obviously not true, and also funny because of the undertones that it’s a clever way to get horny teenagers to study physics who really just want to see the photos.
You are being pedantic, but I’ll play along. Absurd has multiple meanings. It can mean nonsensical, but it can also mean utterly ridiculous or silly. Under those other meanings I believe the pop-star-physics-professor still qualifies.
It sounds pedantic, but "absurd" is fundamentally different from "rare". A lot of baggage comes from flagging something as absurd, instead of just unexpected or uncommon. Winning the lottery isn't absurd, having 3 pairs of some chromosome isn't either, and being a successful pop singer with an academic background isn't either, it's just rare.
Everyone knows Alanis Morissette is a master electrician. That's why she has one hand in her pocket, while the other is probing a circuit.
Anyway, it's kind of Ironic [1] that the dude from Queen is an astrophysicist, and Britney Spears is writing Semiconductor Physics tutorials. Something something music and math.
At the time she was ground zero for all of pop culture and pretty much every single man’s crush. When that website came out it was funny because we were all looking at pictures of Britney anyway so may as well learn some physics at the same time.
Btw, she really went downhill once she fell out of popularity. I think she has a life put back together finally but she got a raw deal. I’m rooting for her.
Others have pointed it out, but it’s the juxtaposition of the fact that she’s definitely not an expert in this subject with a lesson in the subject.
There’s some subtle bits to the humor depending on how charitable you’re feeling. It might just be absurdist, as in “Blackbeard’s guide to astrobiology”, or it may be more mean spirited and playing on a belief that she is not intelligent.
TL;DR - the joke formula is just:
subject=…
person_not_familiar_with_subject=…
joke=“${person_not_familiar_with_subject}’s guide to {subject}“
And the amount of implied cruelty in the comparison is variable.
An attempt was made in the section "Band Structure and Effective Mass" of the chapter "Basic Semiconductor Physics" to tie the two disparate subjects together.
There was a meme that was floating around about the Hawk-Tuah girl analyzing differential equations (IIRC) just last year. I fell for it, though. My son had to explain to me that it was fake.
If I share the OP's objections, which I think I do, the problem isn't with the joke attempt itself, it's with the execution. The joke isn't tied in to the content at all, it's literally just the title, and nothing else.
If the author had tied song references into the text, for example, that would make it a much better execution.
Agree, this is definitely Penguin of Doom level humor. But the mechanic is the same as most comedy - the tickle of surprise from two ideas coming together.
It's just a physics book that happens to have pictures of the popstar in it.